Telephone signaling system.



E. E. HINRICHSEN.

TELEPHONE SIGNALINGSYSTEM.

APPLICATION FILED JULY 19. 1915.

1,230,578. Patented June 19, 1917.

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UNITED STATES PATENT OFFICE.

EDWARD E. HINRICHSEN, OF NEW YORK, N. Y., ASSIGNOR, BY MESNEASSIGNMENTS,

T0 WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TELEPHONE SIGNALING SYSTEM.

Specification of Letters Patent. Patented June 19 1917,

Application filed July 19, 1915. Serial No. 40,687.

To all whom it may concern:

Be it known that I, EDWARD E. HINRIOH- SEN, a citizen of the UnitedStates, residing In accordance with this invention there is provided asignaling device forming a part of the link circuit, said device beingcapable of giving a plurality of signals by varying the strength ofcurrent used to operate said device. Such a signaling device maycomprise a supervisory lamp in an operators cord circuit so arrangedthat the flow of current therethrough may be controlled in such a manneras to give distinctive indications for difierent circuit conditions.

This invention is illustrated diagrammatically in the accompanyingdrawing.

Subscribers substations A and B are connected by means of line wires 1and 2 to a line jack 3 located at the central office. The usual lineequipment, comprising a line relay 4 controlling a line lamp 5 and acut-off relay 6, is associated with each of these hnes. There isprovided at the central oflice an operators cord circuit which includesa source of current, an answering plug 7 and a calling plug 8, and hasconnected in the talking strands supervisory relays 9 and 10respectively.

Upon the initiation of a call by subscriber A, the line relay 4 isenergized in the usual manner, efiecting the lighting of the hue lamp 5.The operator, observing the lighted ing plug 7 into the line jack 3,thereby causing the operation of cutoff relay 6 and supervisory relay 9.The relay 9 in pulling up its armature closes contact 12,. whichcompletes a circuit through relay 13 over the following path: battery,lamp 14, contact 12, conductor 15, coil ofrelay 13, conductor 16,contact 17 to ground. The actuation of the relay 13 automaticallyconnects the operators telephone set inthe cord circuit. It may bementioned here that due to the high resistance of the winding of therelay 13,

the lamp 14 is preventedfrom lighting upon the closure of the circuitjust described.

Assuming that subscriber A desires to converse with subscriber B, theoperator upon learning of this fact inserts the calling plug 8 into theline jack 3. By this operation ringing current is automaticallyimpressed upon the called subscribers line by the energization of theringing relay 18 over the following path: battery, lamp 19, conductor20, contact 21, conductor 22, coil of relay 18, conductor 23, contact 24to ground. It will be noticed that relay 25 was energized when theoperator inserted the plug 8 into jack 3 by the closure of the followingcircuit: battery, coil of relay 25, conductor 26, sleeve side of plug 8and jack 3 respectively, coil of relay6 to ground. It will also be notedthat during the application of the ringing current to the calledsubscribers line, the lamp 19 and the relay 18 are connected in seriesand, due to this fact, the brilliancy of the lamp 19 will be belownormal or less than when no resistance is included in its energizingcircuit. This feature may serve as a signal for notifying the operatorthat ringing current is being sent over the line of subscriber B.

Upon the removal of the receiver by the subscriber at substation B,enough resistance is removed from the line circuit to operate themarginal relay 30, which is energized over the following path: from asource of alternating current through the coil of relay 30, contact 31,ring side of plug 8 and jack 3 respectively, line wire 1, through thesubstation B, returning over line wire 2, tip side of the jack 3 andplug 8 respectively, contact 32 to ground. The energization of theoperation over the following path: battery, condition of line lamp 5,inserts the answerresistance 34, coil of relay 33, conductor 35, 36,contact 24 to ground. The energization ofthe supervisory relay 10 takesplace simultaneously with the energization of the relay 30. It may bementioned here that the relay 30 is of a slow releasing type so as toallow suflicient margin to insure the operation of the relay 33. Theoperation of the relay 33, in pulling up its right-hand armature, opensits back contact 21 and closes its front contact 37. The opening ofcontact 21 effects the denergization of the ringing relay18 and theextinction of the lamp 19. The extinguishing of the lamp 19 may serve asa signal to the operator that the called subscriber has responded. Bythe opening of contact 38 the short circuit about the relay S53 ispermanently removed until it becomes deenergized.

\Vhen the subscribers A and B have linished conversing, upon thereplacement of the receiver at substation B, the supervisory relay 10 isdeene-rgized, which in releasing its arn'iature permits the closure ofcontact d2, thus establishing the following circuit through the lamp 191battery, lamp 19, con.- ductor 20, contact 37, conductor '3, contact 2to ground. It will be noted that the lamp 19 can now burn at its fullbrilliaiuzy due to the fact that no resistance is included in thecircuit just described. The operator upon observing the lighting of thelamp 19 will be informed that the subscriber at substation 13 hasreplaced his receiver upon the switch-hook. The replacement oi thereceiver by subscriber A will effect the lighting of the lamp ll by theclosure of the following circuit: battery, contact 50, conductor 51,contact 24, to ground. The lighting of the lamps l-l; and 19 willindicate to the operator that she is now at liberty to take down theconnection existing between the subscribers A and 13.

From the above it will be apparent that by controlling the strength ofcurrent lloW- ing through a signaling device, a plurality of indicationsmay be obtained from the same device, and each indication may tunetionas a signal for a distinct operation on the part of the operator. Byvirtue of the tact that one of these indications is present during theapplication of ringing current to the line of the called subscriber, thesupervisory work of the operator is greatly re lieved by eliminating thenecessity of her going in on the line of the called subscriber toascertain its condition.

What claimed is:

1. In a telephone system, a subscribers line, a link circuit, a sourceof ringing current, a relay for connecting said source to the line. asignaling device, an operating circuit for and including both the relayand the signaling device completed upon connection ot the link circuitwith the line, means in the link circuit and controlled from the stationon the line for opening the operating circuit, a second operatingcircuit for the signaling device, and means controlled from the stationon the line for completing the second operating circuit.

2. In a telephone system, a subscriber's line, a link circuit, a sourceof ringing current. a relay for connecting said source to the line. asignaling device. an operating circuit for and including both the relayand in the link circuit and controlled from the station on the line foropening the operating circuit, a second operating circuit ofsubstantially lower resistance than the first operating circuit for thesignaling device, and means controlled from the station on the line forcompleting the second operating circuit.

3. In a telephone systei'n, a subseribens line, a link circuit, a sourceof ringing current, a ringing relay for connecting said source to theline, a signaling device, an operating circuit for and including boththe ringing relay and the signaling device conipleted upon connection ofthe link circuit with the line a relay in the link circuit operatingupon removal of the receiver from the switchhook at the station on theline for opening the operating circuit and excluding the ringing relaytherefrom, a supervisory relay, and an operating circuit for thesignaling device alone completed upon the deenergization of thesupervisory relay.

4. In a telephone system, a subscribers line, a. link circuit, a sourceof ringing current, a ringing relay for connecting said source to theline, a signaling device, an operating circuit for and including boththe ringing relay and the signaling device com pleted upon connection ofthe link circuit with the line, a relay in the link circuit operatingupon removal of the receiver from the sivitchhook at the station on theline for opening the operating circuit, a supervisory relay, and asecond operating circuit for the signaling device of substantially lowerresistance than the first ope ating circuit completed upon thedeenergization of the supervisory relay.

5. In a telephone system, a subscribens line, a link circuit, a sourceof ringing current, a ringing relay for connecting said source to theline, a signaling device in the link circuit, an operating circuit forand including both the ringing relay and the signaling device completedupon the connection of the link circuit with the line, a relay in thelink circuit operating upon the removal of the receiver from theswitchhook at the station on the line for opening the operating circuit,a supervisory relay, and a second operating circuit for the signalingdevice of substantially lower resistance than the first operatingcircuit par tially established upon the operation of thesecond-mentioned relay and completely established upon the subsequentde'energization of the supervisory relay.

In 'itness whereof, I hereunto subscribe my name this 15th day of July,A. I). 1.915.

lCDlVARD E. HINRICHSEN.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

